Handle null return value for getLastResortFallbackFont

getNonRetainedLastResortFallbackFont can, despite the name which seems
to suggest otherwise, return 0. Handle this case by bailing out and
asserting.

BUG=341628
R=dglazkov@chromium.org

Review URL: https://codereview.chromium.org/150103014

git-svn-id: svn://svn.chromium.org/blink/trunk@166678 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IDL compiler: Cleanup TestObject.idl and attribute getter template

This cleans up TestObject.idl, removing cases that aren't used.
This allows us to turn it on in Python: all cases pass!

* 'create' attribute (special name)
* [CallWith=ScriptState] attributes
* [CallWith=ExecutionContext] + [RaisesException=Getter] (just order)
* nullable + [RaisesException=Getter] (just order)
* methods with nullable arguments
　(property setters with nullable arguments work fine, but no normal methods)

Also clean up attribute getter in attributes.cpp,
giving some order and putting in FIXMEs for post-Perl cleanup.

BUG=239771
TBR=haraken
NOTRY=true

Review URL: https://codereview.chromium.org/142923004

git-svn-id: svn://svn.chromium.org/blink/trunk@166679 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Rename [GarbageCollected] to [WillBeGarbageCollected]

We need different IDL attributes for transition types and real types in oilpan.
We will use [WillBeGarbageCollected] for transition types and
[GarbageCollected] for real types (which will be implemented in the near future).

Review URL: https://codereview.chromium.org/140663011

git-svn-id: svn://svn.chromium.org/blink/trunk@166680 bbb929c8-8fbe-4397-9dbb-9b2b20218538